Embodiments herein generally relate to printing devices and systems and more particularly to systems that determine the rate at which carrier particles used with toner are dispensed.
An electrostatic printing machine includes a photoconductive member that is charged to a substantially uniform potential to sensitize the surface thereof. An electrostatic latent image is placed on the photoconductive member corresponding to the informational areas contained within a document. After the electrostatic latent image is formed on the photoconductive member, bringing a developer material into proximal contact therewith develops the image.
Typically, the developer material comprises toner particles adhering tribo-electrically to magnetic carrier granules. This mixture is brought into contact with the photoconductive surface. The toner particles are attracted from the carrier granules to the latent image. The carrier granules are then returned to the developer housing where they can be re-supplied with toner particles and where the new toner particles can be prepared with the appropriate tribo-electric charge.
Developer material has several properties including its electrical conductivity and its ability to properly charge toner. As the developer material ages its properties change, and when the material approaches the end of its useful life, copy quality deteriorates. By continuously adding additional new carrier granules to the developer housing, the rate of change of the developer material critical properties can be reduced or eliminated. The carrier replenishment system should provide good regulation of the input of carrier granules into the development unit.